Fluid motor



FLUID MOTOR Filed Dec. 17, 1957 ill! R O T N E V W Y. 1 B WW. 7 7 w 1 w. 1 I H 0 a a L 1 u. L :41 .2

ATTORNEY Patented, Nov. 12, 1940 UNITED STATES PATENT OFFICE MOTOR John F. Wallace, Shaker Heights, Ohio, assignor to The Cleveland Pneumatic Tool Company, Cleveland, Ohio, a corporation Ohio Application December 17, 1937, Serial No. 180,313

7 9 Claims. This invention relates broadly to fluid actuated motors, but more particularly to that type of mechanism incorporated in.an airplane for rals ing or lowering the landing gear thereof.

One object of this invention is to produce a fluid actuated motor including a cylinder having a fluid actuated piston reciprocable therein, with means for automatically locking the piston at the end of its strokes, thereby preventing the accidental axialmovement of the piston relative to its cylinder and the consequential collapse of the landing gear in the event of a failure 01' the fluid pressure within the cylinder.

Another object of this invention is to produce '15 a fluid motor of simple construction forming a compact and light assembly which is strong, durable and eflicient.

In the drawing:

Fig. l is a longitudinal sectional view of a fluid motor embodying the invention shown in retracted position.

Fig. 2 is a view similar to Fig. 1 showing the motor in extended position.

Fig. 3 is a cross sectional view taken in a plane indicated by line 3-3 in Fig. l.

Fig. 4 is an enlarged longitudinal sectional view of a portion of the lower end .of the motor, illustrating the locking device about to be driven 30 into operative position.

Referring to the drawing in which like symbols designate corresponding parts throughout the several views, l0 represents a hollow cylinder having its upper end internally threaded as at- H to slots'li also extend through the sleeve H,- and 5 each has a detent or dog I! slidable therein with a tapered end l8 movable into and out of the interior of the sleeve l4, and a step l9 engage- 45 able with the exterior of the ring for limiting its inward movement. The ring I5 is alsoformed with an annular groove 20 opening into the cylinder l0 and extending across the dogs Nor-' mally this groove is of a U-shape cross section,

50 but in the dogs II, the inner side wall of the groove is tapered as at 2|. Externally,-the ring I5 is provided with longitudinally disposed grooves or passages 22 affording communication between the upper end of the cylinder l0 and an 55 annular chamber 23 formed within the head 12,

which contains a stufilng box including packings 5 28 and an adjustable nut 29. On the head 21 is also secured a ring 30 which is similar to the ring l5 above described. This ring also carries slidable detents or dogs 3| formed with a tapered inner end 32, and has-an annular groove 33 also 10 v extending across the dogs 3|. The groove 33 is similar to the groove 20, with its inner side wall 1 within the dogs 3| tapered as at 34. On the external wall of the ring 30, there are passages not i shown which are similar to the passages22 to 13 afl'ord communication between the lower end of the cylinder and an annular chamber 35 formed within the head 21, which'chamber communicates with a fluid conduit connection 36 through a passage 31. 20 Slidable through the. lower head 21, there is a piston-rod 38 having its outer end formed with a bracket 39 for connection to the landing gear of an airplane. Toward its end, the piston-rod is formed with a reduced portion or neck 40 having 25 a collar 4| rigidly secured thereon.

Slidably mounted on the collar 4|, there is a piston generally designated by 42' and comprising a head 43 formed with an intumed flange 44 engageable with the collar 4| for limiting axial movement of the piston in one direction. From the flange 44 depends a short sleeve or annular step 45 adapted to fit into the groove 33 of the ring 3|. The piston head is threaded as at 46 to receive amp 4'! also formed with an intumed 35 flange l3 engageable with the collar for limiting slidable movement of the piston in the other direction. Extending from the flange 48, there is an annular step 43 adapted to fit into the annular groove 20 of the upper ring. IS. The dis- 4 tance between the piston intumed flanges and 48 is somewhat greater than the length of the collar 4|, allowing limited axial movement of the piston relative to the collar. Clamped between' the piston head '43 and its companion cap 41, 45 I to exhaust through the other.

the dogs 3|.

1, the motor is in retracted position with the tapered ends |8 of the dogs I! located into the V- shaped groove 52, thereby preventing axial movement of thepiston-rod 38 relative to the cylinder iii. In this instance, it will alsobe noted that the annular step 59 of the piston 32 is located into the annular groove formed within the ring i5 and extending across the dogs ll, thereby preventing the accidental lateral movement or release of the dogs I? relative to the piston- 1 rod 38. When motive fluid is admitted into the connection 2 3, it will flow through the passage into the annular chamber 23, and therefrom on the cap 81 of the piston 42 through the passages 22. The motive fluid thus acting on the piston 32, will cause the latter to move axially relative to the piston-rod 38 until the inturned flange 38 engages the collar M; During this movement of the piston relative to the piston-rod, the annular step 49 will move out of the annular groove 28 for allowing the lateral movement or release of the dogs ll. As the inturned flange 48 of the piston 42 engages the collar 4|, the motive fluid will also be admitted on the adjacent upper end wall of the collar 4|, thereby cooperating with the piston for imparting axial movement to'the piston-rod 38, causing the upper side wall of the V-shaped groove 52 to act on the tapered ends I3 oi the dogs I1 for automatically effecting the release of the dogs.

During the downward movement in Fig. 1 or the piston-rod 38, themotive fluid previously admitted into the cylinder! between the piston 42 and the lower head 21, is free to exhaust through the connection 36. As the piston rod 38 approaches the end of its downward stroke, the piston 42 is positioned as shown in Fig.4 relative to the collar 4|, that is with the inturned flange 48 resting on the collar 4|, thereby causing the annular step 45 of the piston 42 to engage the inclined side wall 34 of the annular groove 33 of 5| of the rod 38 being not yet aligned with the dogs 3|, the piston 42 having motive fluid acting thereon will momentarily remain stationary while drivingly acting on the dogs in an eflort to move them inwardly. Simultaneously, the piston rod 3 8, due to the action of the motive fluid on the upper end wall of its collar 4|, will continue in its downward movement until the' groove 5| is positioned in alignment with the dogs 3|, in which instance, the dogs 3|, due to the driving action of the piston annular flange 48 on the inclined side wall 34, will be driven into the annulargroove SI for locking the piston rod 38 against axial movement relative to the cylinder l0. As the dogs are driven inwardly into the groove 5| of the 'rod 38, the portion of the groove 33 within the dogs 3| will move into alignment with'the rest oi the groove within the ring 38,-therebyenab1ing the piston 42 to move into the position shown in Fig. 2, with its annular step 45 located within the annular groove 33 for preventing accidental lateral movement or release of the dogs.

When it is desired to retract or collapse the As shown in Fig.

In this instance, the annular groove motor, motive fluid may be admitted into the conmotion 83 and exhausted through the connection 2 5. In this instance, the motive fluid from the connection 38 will flow into the annular chamber 35 through the passage 31, and from the chamber 85 on the piston head 35 through passages,.not shown, which are similar tothe passages 22 and are provided on the peripheral wall of the ring 38. The motive fluid acting on the piston head 33 will effect the axial movement of the piston 82 I relative to the collar 4| until the inturned flange 43 engages the collar 4|. This initial movement of the piston will cause its annular step 35 to move out of the annular groove 33 for allowing the lateral movement of the dogs 3 Thereafter, the motive fluid acting on the lower face of the piston 32 will also be admitted on the adjacent lower face. of the collar 3|, thereby cooperating with the action of the lower inturned flange d6 of the piston on the collar 4H for driving the rod 38 upwardly, thus resulting in the lower inclined side wall of the V-shaped annular groove 5| to act on the tapered end 32 of the dogs 8| for automatically efiecting the release of the dogs.

During the upward movement in .Fig. 2 of the piston rod 38, the motive fluid previously admitted into the cylinder It between the piston 32 and the upper head i2, is free to exhaust through the connection 24. As the piston rod as reaches the end of its upward stroke, the annular step 33 of the piston 42 will exert pressure on the inclined side wall 2| of the annular groove 23 within the dogs ll, tending to move the dogs inwardly. However, since the V-shaped annular groove 52 of the rod 38 is" not yet in alignment with the dogs H, the piston will momentarily remain stationary while the rod 38, due to the action of the motive fluid on the lower end wall of the collar 4|, proceeds upwardly. When the groove 52 is finally in alignment with the'dogs H, the dogs will be driven into the groove as and groove 33, thereby locking the piston rod 38 at the end of its inward stroke.- As the dogs I? are driven inwardly, the portion of the groove 20 within the dogs will also move into alignment with the rest of the groove within the ring i5, thereby enabling the piston 42 to move into the position shown in Fig. 1, with its annular step 43 located within the annular groove 20 for preventing accidental lateral movement or release of the dogs.

When the piston rod 38 is away from the upper head member l2, it is possible for the dogs i1 carried by this upper head to accidentally assume the position shown in Fig. 2. In this instance, during the upward movement in Fig. 2 of the piston-rod 38, the inner tapered end 53 of the piston-rod will first engage the tapered end It of the dogs H, for driving the dogs outwardly to allow the free passage of the inner end of the piston-rod 38 into the sleeve l4 of the upper head It.

From the foregoing description, it will be understood that when the piston rod 38 has gagement with thedogs I] or unaii'ected by a failure or the motive fluid pressure into the cyl-. inder. l0.

' Although the foregoing description is m sarily of a detailed character, order to completely set forth the invention, it is to be understood that the specific terminology is not intended to be restricted or confining and it is to be fur-v ther understood that various rearrangements of parts and'modiflcations of structural detail may beresorted to without departing from the scope or spirit of the invention as herein claimed. I claim: 1. In a fluid motor, an elongated casing having motive fluid admitted therein,. a piston and piston-rod subjected to the pressure of said motive ,fluid for reciprocation within said casing, said piston and rod being capable 0! limited relative axial movement, locking means between said casing'and rod including a recess on said rod, a detent carried by said cylinder adapted to extend into said recess for preventing relative reciprocation between said cylinder and rod when said ron reaches the end of its stroke in one direction and automatically releasable upon movement or said piston and rod in the other direction, and means on said piston drivingly engaging said detent during said relative axial movement for,

casing adapted to extend into said recess for pre-" 35 venting relative reciprocation between said casing and rod, means on said piston engageable with said detent for shifting the same intooperative position during said relative axial movement in one direction, and means on said rod responsive o to the initial movement of said piston and rod in the other direction ior automatically effecting the release of said detent;

" 3. In a fluid motor, a cylinder, a rod'reciprocable therein, means admitting motive fluid into 5 said cylinder for actuating said rod, a lock for said rod'including a detent carried by said cylinder inwardly-slidable intoioperative' engagement with the, rod for locking the rod atone end of its stroke, and a motive fluid actuated reciproca- 50 ble piston within said cylinder normally assisting in the reciprocation of said rodanddrivin'gly acting on said detent near the aforesaid end of said stroke ror eflecting the operative engagement thereof with said rod. 66

' ed elements, a lock between said elements including a detent carried by one of said elements radially slidable inwardly into operative' engagement .with the other element for preventing relaoo tive movement therebetween, and fluid actuated means between said elements engageable with said'ifletent tor eflecting its inward slidable movemen 66 arodtelescopically therein,alocking 4, In a fluid'motor, a pair telescopically mount 3 for locking the rod at the end of one of its strokes including a recess on the. rod, a detent carried by the cylinder adapted to extend into said recess, and means on said'rod movable in one direction for shifting and holding said detent in said recess and in the other direction to enable said detent-to move out of said recess.

63% fluid actuated motor including a cylinder,

a rod telescopically therein, a piston on the rod capable of limited slidable movement relative thereto, a locking mechanism between said cylin-' a rod telescopically therein, a; double-acting sleevelike piston. on the rod capable of limited slidable movement relative thereto, a locking member carried by the cylinder engageable with the rod for looking it at the end of one of its strokes,. and interengageabie camming means on said piston and member operable by virtue of the relative slidable movement between said rod and piston for efiecting operative engagement of said member with said rod.

8. In a fluid actuated motor, an elongated casing, a fluid actuated piston and rod reciprocable within said casing, said piston and rod being capable of limited axial relative movement, passages !or admitting motive fluid into said casing for actuating said piston and rod, a locking member within one end of said casing slidable radially relative thereto into operative engagement with said rod for preventing its reciprocation and capable oi release to enable said reciprocation, interengageable camming means on said member and piston operable by virtue of said axial. relative movement for automatically effecting operative engagement of said member with said rod near .the end of the stroke of said'rod in'one direction, and camming means on said rod and member' operable upon initial movement of saidrod in the otherdirection for efiectingvsaidrelease.

9. A fluid actuated motor including inner and outer telescoping elements," a stationary head within one end of the outer element,- a locking member within said head slidable radially into operative engagement with the inner member for preventing telescopic movementof said elements and capable of release to enable said ni ovement, a sleeve carried by the inner element capable of limited axial movement relative thereto, an inclined surface on said sleeve engageable with said member near the end of the stroke of said inner element or automatically effecting said operative engagement, and an inclined surface on said. inner element engageable with said member for effecting said release upon initial movement or the inner element in the other direction. I

-- JOHN F. WALLACE. 

